JOURNAL OF CHEMICAL EDUCATION
A RAPID TEST FOR CASTOR OIL IN SOAPS AND LIPSTICKS1 SISTER M. CLARITA MANGOLD Rosary Hill College, Buffalo, New York
Vizern and Guillotz present a method for the characterization of castor oil in mixtures of fatty materials. It is based on the fact that ricinoleic acid (the chief fatty acid of castor oil) with excess of alkali forms capryl alcohol (see. octyl alcohol), one of the eighty-nine isomers of octyl alcohol. excess NaOH
CH3(CH2)&HOHCHaCH=CH(CH2hCOOH Rioinoieio Acid
NaO&(CH&2OaNa Sodium Sebaoate
+
CIHuCHOHCHs Octyi Aloohol
Octyl alcohol has a peculiar, strong, aromatic odor which cannot easily be mistaken. This method was tried on castor oil "as such," and on lipsticks with known amounts of castor oil and found to be valid. However, the author discovered that the method may he greatly simplified and the test applied in a few minutes with very small amounts of materials. There is no need of separating castor oil from other constituents. It is not necessary to carry out the long 1 Partly taken from a. thesis submitted to St. Bonaventure College, St. Bonaveuture, New York (1949). 1 VIZERNAND GUILLOT,Chem. Abstracts, 21, 1198 (1927).
process of saponification nor to follow the procedure given by Visern and Guillot. It was found that other oils, fats, waxes, dyes, fillers, perfumes, etc., did not interfere with the formation and identification of octyl alcohol. PROCEDURE
Put about one gram of a soap or lipstick into a test tuhe, add three pellets of sodinm or potassium hydroxide and heat gently, shaking occasionally until heavy white fumes form. Cover, and let cool, then smell the contents. (The odor of octyl alcohol can be detected even when hot.) The odor of octyl alcohol indicates the presence of castor oil. If water is added to the test tuhe when cool, the odor is still more pronounced. This rapid test was applied t o the pure oil, t o laboratory lipsticks and soaps having varying amounts of castor oil, and to six commercial lipsticks. All these, except one commercial lipstick, responded to the test. The laboratory lipsticks and soaps were purposely highly perfumed to find out if this interfered with the odor of octyl alcohol. As low as 10 per cent of castor oil was detected by this method.
